Cause : Motor overload trip comes when the electronic thermal O/L relay function in the inverter detects motor overheat, which is caused by overload or reduced cooling capability during low-speed operation. When the cumulative heat value reaches 85% of the Pr.9 Electronic thermal O/L relay setting, pre-alarm (TH) is output. When the accumulated value reaches the specified value, the protection circuit is activated to stop the inverter output.

1. Check the motor for the use under overload.
2. Check that the setting of Pr.71 Applied motor for motor selection is correct.
3. Check that the stall prevention operation setting is correct.
4. Reduce the load.
5. For a constant-torque motor, set the constant-torque motor in Pr.71.